Many communities as well as local and state governments have implemented zero-waste strategies, where they utilize the reduce, reuse, recycle, and compost (or 3RC) strategy, WTE, and landfill as a path to minimize the potential for pollution of air and ground water.
Many communities and government organizations have concluded that zero waste is currently unattainable. A major effort to minimize packaging of marketed items is being made through changing policy. Recycling efforts are also being implemented successfully by many organizations.
Reduction of greenhouse gasses (GHGs) is another consideration during the life-cycle evaluations of waste management practices. Some communities are far enough away from the recycle markets that some of the recyclable materials are not economically and environmentally justified to include as part of their near-term recycle goals. The carbon footprint can potentially increase due to shipping materials to the market, compared to utilizing the recyclable material as a feedstock for a WTE facility or to continue sending the material to a landfill.
Waste-to-energy technologies consist of various methods for extracting energy from waste materials. These methods include thermochemical and biological methods.
The Figure below provides an illustration of the various energy pathways for WTE. Of these pathways, most are maturing from early developmental stages. Currently the WTE technologies that are commercially proven world-wide using MSW feedstock are combustion, anaerobic digestion and pyrolysis. All other processes hold high potential for utilizing MSW feedstock, but must overcome various technical, institutional, economic, environmental, and/or procedural challenges to become commercially viable.
The primary challenge facing these technologies is the heterogeneous nature of MSW, which creates a widely varying chemical constituency of the energy products generated from these processes. This variance affects the ability to efficiently extract energy. Solutions are actively being pursued from two angles.